London: The old tried and true methods of eating less fat, exercising and joining weight loss programs are more effective strategies for shedding those extra kilos than popular diets and non-prescription pills, researchers say.

lead author Jacinda M. Nicklas, MD, MPH, MA, a clinical research fellow at Beth Israel Deaconess Medical Center and Harvard Medical School and colleagues analysed data from more than 4,000 obese individuals culled from the 2001-2006 National Health and Nutrition Examination Survey conducted by the Centers for Disease Control and Prevention to assess the health and nutritional status of adults in the United States"This is great news because studies have shown that even a 5 percent reduction in weight can lead to improved health," said Nicklas.

"With more than a third of Americans now obese and fifty to seventy percent of them trying to lose weight, this is important because the health risks associated with carrying that extra weight are substantial."

Individuals included in the study were over 20 years of age with a body mass index of 30 or more 12 months prior to the interview.

Of those surveyed, 2,523 individuals reported trying to lose weight. Forty per cent of these said they experienced weight loss of 5 per cent or greater, and another 20 per cent lost 10 per cent or more.

"Those who exercised more and ate less fat were significantly more likely to lose weight," said the authors."Additionally we found a correlation between joining weight loss programs and greater reported weight loss, which may speak to the importance of structure in a weight loss regimen," said Nicklas.

And while those who used prescription weight loss medications also reported weight loss success, this represented only a small number of study participants.

In contrast, the authors found that, "self-reported use of popular diets, liquid diets, nonprescription weight loss pills and diet foods/products were not associated with weight loss."

"It''s very encouraging to find that the most of the weight loss methods associated with success are accessible and inexpensive," said senior author Christina Wee, MD, MPH who conducts research on obesity and health disparities as the Co-Director of Research in BIDMC''s Division of General Medicine and Primary Care.

"There are lots of fad diets out there as well as expensive over-the-counter medications that have not necessarily been proven to be effective, and it is important that Americans discuss product claims with their doctor before trying such products," Wee added.

This study did not look at the long-term impact of these interventions on an individual''s ability to keep the weight off. The authors suggest that future research is needed to identify and address barriers to maintaining weight loss. The study has been published in the American Journal of Preventive Medicine.